Extremely light bosons and axion-like particles have been proposed to solve various problems in fundamental physics and cosmology. These particles can exhibit quantum behavior on large scales, extract rotational energy from astrophysical black holes, and form large “boson clouds.” In our recent paper in Nature Astronomy Letters (see also this blog post) we show that a single gravitational-wave observation of extreme mass-ratio inspirals (EMRIs) by the forthcoming Laser Interferometer Space Antenna (LISA) could be used to find out if such light bosons exist in nature.
